Development Of A New Coal Permitted Detonating Cord

Industrial detonating cord is a priming (principal priming materials)which is widely used in blasting engineering. In large blasting engineering with multiporous, detonating cord used as a detonating network. The maximum advantage is can avoid explosion of electric detonator caused by stray current on ground or lightning induction in air and detonate the explosive in blast hole.In the deep-hole blasting in coal mining face containing gases, in which the depth of the hole often exceed 3.5m and decoupling charge coefficient is 1.1-2.8, the spread length of explosive detonation will decrease and even failure because of the effect of pipeline. When the deep-hole blasting is carried out in low air permeability and high gas outburst seam, the depth of a hole is dozens of meters, only one detonator cannot guarantee the reliability of detonation transmission. Detonating cord which detonation velocity is high can effectively overcome dead pressed effect of pipeline effect on explosive. So developing a kind of detonating cord permitted in coalmining and its high detonation velocity can effectively maintain the reliability of detonation transmission in mine well which containing gases are necessary.At present, the coal mine permitted detonating cord diameter is greater than 8mm and its flexibility is poor. When the coal mine permitted detonating cord lapped over each other, the detonation waves can't spread perfectly. So the coalmine permitted detonating cord can't be used widely in the coalmine deep-hole blasting. In order to decrease the diameter of coal mine permitted detonating cord and improve its flexibility to insure the detonation transmission when the coal mine permitted detonating cord lapped over each other, the components of coalmine permitted detonating cord, formula and technology were selected based on the theory calculation of blasting heat, blasting temperature, detonation velocity, the influence of flame reducer on the gas safety and the explosion properties of high explosive. The products are tested and used in deep-hole blasting coal. The tests result show that the detonating cord wrapped by flame reducer tube not only solves the safety probiom of the coal permitted detonating cord but also pledge the explosion properties of the coal permitted detonating cord. The formula of the coal permitted detonating cord is PETN: flame reducer a=93-95:5-7. the charge desity is 10-12g/m. the weight of the flame reducer tube is 4-6g/m, the diameter of the coal permitted detonating cord is 6.2-6.8mm. The formulation design of the coal permitted detonating cord is reasonable and explosion transfer performance is reliable and the structure design of the coal permitted detonating cord is reasonable. The numerical simulation show safety performance and explosion property of the coal permitted detonating cord are reliable. Figure 27 Table 15 Reference 29...